Thanks a lot guys, not much under the hood actually Rod, a very small skimmer for this size tank(IM 1000), its the same one i used on a 400litre system actually. I run carbon 24/7 about 700g and replace twice a month, the sand bed seen above has 3 4ft tubes and a whole lot of chaeto and pipe fish now and the large fairly empty sump tank has about 40 kenyan live rock to assist with overall filtration. Thanks a lot to Wessel for his time and patience!